Rumford fireplaces influenced chimney design in America. Before 1796 - before Rumford published his first essay on fireplace design - fireplaces were deep, and the chimneys built to vent these deep fireplaces that extended through the exterior wall, were logically built outside of the exterior walls of the house.

Williamsburg, 1760

A chimney in Williamsburg, for example, restored to about the 1760, before Rumford did his fireplace work, is outside the structure of the building.

Notice the separation between the chimney and the roof for fire safety. Fire safety strategies, too, have changed over the years. See sidebar.

This Tidewater Colonial house built in 1750 can be dated "before Rumford" because the chimney is built on the outside of the exterior wall to accommodate a deep pre-Rumford fireplace.

Tidewater Colonial, 1750

Norfolk, VA c 1807

After 1796, when the shallow reflective Rumford fireplaces swept the country, chimneys came inside or were incorporated into the exterior walls of the house because it was easier to build the chimneys over the shallow fireplaces rather than to slope the flues to reach through the wall to an exterior chimney.

Ontario, Canada c 1844

Victorian chimneys were often a lot fancier but the fireplaces were small, shallow coal or gas fireplaces that were patented variations of the older Rumford fireplaces.

Because of the shallow fireplaces, the chimneys were still, generally, part of, or inside, the exterior walls of the house.

Shallow fireplaces and inside chimneys lasted up through the 1930's and 1940's. The 1930's house on the left was built to vent a coal furnace and a shallow gas fireplace which you can tell by the 8"x8" and 8"x12" flues protruding from the top of the chimney. The 1917 house on the right vented two gas fireplaces.

By the 1950's ranch houses were popular and so was "central heating". Fuel was cheap. Fireplaces were not required for heating. Fireplaces were "optional". You might say fireplaces were re-invented to look horizontal so they would fit with the ranch style architecture. Fireplaces were also made deeper than they had been for 150 years to help keep them from smoking and, for the first time since the 18th century, chimneys were again built on the outside of the house.

Into the 1970's and 80's fireplaces were "optional" and chimneys (increasingly sided with wood to hide metal chimneys) were tacked on the outside of the house.

There are some "period homes" being built. But, even if the detailing is pretty good, often you can tell that it's not really an old home by the chimney. This new house, which looks as if it might have been built about 1890, would look more authentic with a smaller barrel chimney inside the exterior wall and only visible above the roof.